1. Field of the Invention
The present invention relates to a cleaning apparatus and, more particularly, it relates to a cleaning apparatus wherein matters such as semiconductor wafers to be processes are carried to cleaning units by carrying robot arms and immersed in and cleaned by cleaning liquids in the cleaning units.
2. Description of the Related Art
The cleaning apparatus is usually used in the semiconductors manufacturing process to remove cleaning liquid and other impurities, which have adhered to surfaces of semiconductor wafers, from the wafers. This cleaning apparatus is intended to make the surfaces of semiconductor wafers clean by successively applying ammonia-treating, water-washing and hydrofluoric acid-treating steps to the wafers.
The conventional cleaning apparatus, therefore, has plural cleaning units in each of which ammonia-treating, water-washing and hydrofluoric acid-treating tubs are housed. Matters such as semiconductor wafers to be processed are held and carried into and out of the cleaning units by carrying systems. Each of the treating tubs is enclosed by a wall in this case so as to prevent atmosphere in each of the cleaning units from leaking outside. The chamber thus formed is provided with openings through which the semiconductor wafers are carried into and out of the chamber.
In the case of this cleaning apparatus, however, the carrying system or robot carries the semiconductor wafers into and out of the cleaning units or chambers whose atmospheres are different from each other. This causes medicines used at previous steps and dust and impurities to sometimes adhere to the carrying system. The semiconductor wafers carried can be, therefore, contaminated by these medicines, dust and impurities and this adds undesired influences to electrical characteristics of semiconductor circuits thus formed.